Articulations of the Digits: Difference between revisions

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Anatomy > Gray's Anatomy of the Human Body > III. Syndesmology > 6k. Articulations of the Digits

Henry Gray (1821–1865). Anatomy of the Human Body. 1918.

Articulations of the Digits of the Hand[edit]

(Articulationes Digitorum Manus; Interphalangeal Joints)

The articulations of the fingers—specifically the interphalangeal joints—are a series of hinge joints that permit flexion and extension between the phalanges of the hand.

Articulations of the digits (posterior view)

Articulations of the digits (lateral view)

There are two interphalangeal joints in each finger:

The proximal interphalangeal joint (PIP) – between the proximal and middle phalanges.
The distal interphalangeal joint (DIP) – between the middle and distal phalanges.

The thumb, having only two phalanges, possesses a single interphalangeal joint.

Ligaments of the Interphalangeal Joints[edit]

Each interphalangeal joint is stabilized by three primary ligaments:

Palmar ligament (volar plate): A thick, fibrocartilaginous band that reinforces the anterior side of the joint capsule and limits hyperextension.
Collateral ligaments: Paired medial and lateral bands that provide lateral stability and help guide motion during flexion and extension.
The extensor tendons serve the function of posterior ligaments, as the joints lack distinct posterior reinforcement.

Movements[edit]

The interphalangeal joints permit the following:

Flexion: Bending the finger toward the palm.
Extension: Straightening the finger from a flexed position.

Flexion is more pronounced at the proximal interphalangeal joint (PIP) than at the distal interphalangeal joint (DIP). Extension is restricted by the volar and collateral ligaments.

Muscles Acting on the Joints of the Digits[edit]

Metacarpophalangeal Joints (MCP)[edit]

Flexion:

Flexor digitorum superficialis Flexor digitorum profundus Lumbricals Palmar interossei and dorsal interossei Flexor digiti minimi brevis (for little finger)

Extension:

Extensor digitorum Extensor indicis Extensor digiti minimi

Interphalangeal Joints[edit]

Flexion:

Flexor digitorum superficialis (acts on PIP) Flexor digitorum profundus (acts on PIP and DIP)

Extension:

Lumbricals and interossei muscles (via their insertion into the extensor expansion) Extensor digitorum plays a limited role directly

Thumb Joints[edit]

Flexion of MCP joint:

Flexor pollicis brevis Flexor pollicis longus

Extension of MCP joint:

Extensor pollicis brevis

Flexion of interphalangeal joint:

Flexor pollicis longus

Extension of interphalangeal joint:

Extensor pollicis longus

Functional Importance[edit]

The interphalangeal and metacarpophalangeal joints are essential for precise hand movements, grasping, and manual dexterity. These joints are stabilized by a complex interplay of passive (ligaments) and dynamic (muscular) support systems. Disruption of any of these structures can result in impaired function, such as in cases of arthritis, tendon injury, or joint instability.

Gray's Anatomy[edit]

Anatomy atlases (external)[edit]

[1] - Anatomy Atlases

Adapted from the Classic Grays Anatomy of the Human Body 1918 edition (public domain)

@@ Line 1: / Line 1: @@
+{{SI}}
+[[Anatomy]] > [[Gray's Anatomy|Gray's Anatomy of the Human Body]] > III. [[Syndesmology]] > 6k. '''Articulations of the Digits'''
-[[Anatomy]] > [[Gray's Anatomy| Gray's Anatomy of the Human Body]] > III. Syndesmology > 6k. Articulations of the Digits
+[[Henry Gray]] (1821–1865). ''Anatomy of the Human Body''. 1918.
-[[Henry Gray]] (1821–1865).  Anatomy of the Human Body.  1918.
+== '''Articulations of the Digits of the Hand''' ==
+'''(Articulationes Digitorum Manus; Interphalangeal Joints)'''
-== ''' Articulations of the Digits'''  ==
-'''(Articulationes Digitorum Manus; Interphalangeal Joints) (Figs. 337, 338)'''
+The articulations of the [[fingers]]—specifically the [[interphalangeal joints]]—are a series of [[hinge joints]] that permit flexion and extension between the [[phalanges]] of the [[hand]].
-The interphalangeal articulations are [[hinge-joints]]; each has a volar and two collateral ligaments. The arrangement of these ligaments is similar to those in the metacarpophalangeal articulations. The Extensor [[tendons]] supply the place of [[posterior]] ligaments.
+[[File:Gray337.png|thumb|Articulations of the digits (posterior view)]]
+[[File:Gray338.png|thumb|Articulations of the digits (lateral view)]]
-=== '''Movements''' ===
-The only movements permitted in the interphalangeal joints are [[flexion]] and [[extension]]; these movements are more extensive between the first and second [[phalanges]] than between the second and third. The amount of flexion is very considerable, but extension is limited by the [[volar]] and collateral ligaments.
-=== '''Muscles Acting on the Joints of the Digits''' ===
-Flexion of the metacarpophalangeal joints of the fingers is effected by the Flexores digitorum sublimis and profundus, [[Lumbricales]], and Interossei, assisted in the case of the little finger by the Flexor digiti quinti brevis. Extension is produced by the Extensor digitorum communis, Extensor indicis proprius, and Extensor digiti quinti proprius.
-Flexion of the interphalangeal joints of the fingers is accomplished by the Flexor digitorum profundus acting on the proximal and distal joints and by the Flexor digitorum sublimis acting on the proximal joints. Extension is effected mainly by the Lumbricales and Interossei, the long Extensors having little or no action upon these joints.
-Flexion of the metacarpophalangeal joint of the thumb is effected by the Flexores pollicis longus and brevis; extension by the Extensores pollicis longus and brevis. Flexion of the interphalangeal joint is accomplished by the Flexor pollicis longus, and extension by the Extensor pollicis longus.
+There are two interphalangeal joints in each finger:
-{{grays}}
+* The '''proximal interphalangeal joint (PIP)''' – between the proximal and middle phalanges.
+* The '''distal interphalangeal joint (DIP)''' – between the middle and distal phalanges.
+The '''thumb''', having only two phalanges, possesses a single '''interphalangeal joint'''.
+== '''Ligaments of the Interphalangeal Joints''' ==
+Each interphalangeal joint is stabilized by three primary ligaments:
+* '''[[Palmar ligament]] (volar plate)''': A thick, fibrocartilaginous band that reinforces the anterior side of the joint capsule and limits hyperextension.
+* '''[[Collateral ligaments]]''': Paired medial and lateral bands that provide lateral stability and help guide motion during flexion and extension.
+* The [[extensor tendons]] serve the function of '''posterior ligaments''', as the joints lack distinct posterior reinforcement.
+== '''Movements''' ==
+The interphalangeal joints permit the following:
+* '''[[Flexion]]''': Bending the finger toward the palm.
+* '''[[Extension]]''': Straightening the finger from a flexed position.
+Flexion is more pronounced at the proximal interphalangeal joint (PIP) than at the distal interphalangeal joint (DIP). Extension is restricted by the volar and collateral ligaments.
+== '''Muscles Acting on the Joints of the Digits''' ==
+=== '''Metacarpophalangeal Joints (MCP)''' ===
+* '''Flexion''':
+''' [[Flexor digitorum superficialis]]
+''' [[Flexor digitorum profundus]]
+''' [[Lumbricals]]
+''' [[Palmar interossei]] and [[dorsal interossei]]
+''' [[Flexor digiti minimi brevis]] (for little finger)
+* '''Extension''':
+''' [[Extensor digitorum]]
+''' [[Extensor indicis]]
+''' [[Extensor digiti minimi]]
+=== '''Interphalangeal Joints''' ===
+* '''Flexion''':
+''' [[Flexor digitorum superficialis]] (acts on PIP)
+''' [[Flexor digitorum profundus]] (acts on PIP and DIP)
+* '''Extension''':
+''' [[Lumbricals]] and [[interossei]] muscles (via their insertion into the extensor expansion)
+''' [[Extensor digitorum]] plays a limited role directly
+=== '''Thumb Joints''' ===
+* '''Flexion of MCP joint''':
+''' [[Flexor pollicis brevis]]
+''' [[Flexor pollicis longus]]
+* '''Extension of MCP joint''':
+''' [[Extensor pollicis brevis]]
+* '''Flexion of interphalangeal joint''':
+''' [[Flexor pollicis longus]]
+* '''Extension of interphalangeal joint''':
+''' [[Extensor pollicis longus]]
+== '''Functional Importance''' ==
+The interphalangeal and metacarpophalangeal joints are essential for precise hand movements, grasping, and manual dexterity. These joints are stabilized by a complex interplay of passive (ligaments) and dynamic (muscular) support systems. Disruption of any of these structures can result in impaired function, such as in cases of arthritis, tendon injury, or joint instability.
+== '''See Also''' ==
+* [[Phalanges]]
+* [[Hand]]
+* [[Extensor mechanism of the hand]]
+* [[Flexor tendons of the hand]]
+* [[Interphalangeal joints of the foot]]
+{{Joints of upper limbs}}
+{{Portal bar|Anatomy}}
+{{DEFAULTSORT:Interphalangeal Articulations Of Hand}}
+[[Category:Joints]]
+[[Category:Hand anatomy]]
+[[Category:Upper limb anatomy]]
+[[Category:Synovial joints]]
+{{grays adapted}}